Electro-optical Sensors Research Study and Astronomical Observations Semiannual Progress Report, 15 Jun. - 15 Dec. 1965

Astronomical observations of short period cluster variables, image orthicon tube performance stability research, and development of strong field magnetically focused image tube

Stability of fluorescence of sodium salicylate

Sodium salicylate fluorescence stability over long periods of time - prevention of contamination by impuritie

Factorization and reduction methods for optimal control of distributed parameter systems

A Chandrasekhar-type factorization method is applied to the linear-quadratic optimal control problem for distributed parameter systems. An aeroelastic control problem is used as a model example to demonstrate that if computationally efficient algorithms, such as those of Chandrasekhar-type, are combined with the special structure often available to a particular problem, then an abstract approximation theory developed for distributed parameter control theory becomes a viable method of solution. A numerical scheme based on averaging approximations is applied to hereditary control problems. Numerical examples are given

Development and Verification of a Flight Stack for a High-Altitude Glider in Ada/SPARK 2014

SPARK 2014 is a modern programming language and a new state-of-the-art tool set for development and verification of high-integrity software. In this paper, we explore the capabilities and limitations of its latest version in the context of building a flight stack for a high-altitude unmanned glider. Towards that, we deliberately applied static analysis early and continuously during implementation, to give verification the possibility to steer the software design. In this process we have identified several limitations and pitfalls of software design and verification in SPARK, for which we give workarounds and protective actions to avoid them. Finally, we give design recommendations that have proven effective for verification, and summarize our experiences with this new language

Non-circular features in Saturn's D ring: D68

D68 is a narrow ringlet located only 67,627 km (1.12 planetary radii) from Saturn's spin axis. Images of this ringlet obtained by the Cassini spacecraft reveal that this ringlet exhibits persistent longitudinal brightness variations and a substantial eccentricity (ae=25+/-1 km). By comparing observations made at different times, we confirm that the brightness variations revolve around the planet at approximately the local orbital rate (1751.6 degrees/day), and that the ringlet's pericenter precesses at 38.243+/-0.008 degrees/day, consistent with the expected apsidal precession rate at this location due to Saturn's higher-order gravitational harmonics. Surprisingly, we also find that the ringlet's semi-major axis appears to be decreasing with time at a rate of 2.4+/-0.4 km/year between 2005 and 2013. A closer look at these measurements, along with a consideration of earlier Voyager observations of this same ringlet, suggests that the mean radius of D68 moves back and forth, perhaps with a period of around 15 Earth years or about half a Saturn year. These observations could place important constraints on both the ringlet's local dynamical environment and the planet's gravitational field.Comment: 39 Pages, 11 Figures accepted for publication in Icarus Text slightly modified to match corrections to proof

Performance and operational economics estimates for a coal gasification combined-cycle cogeneration powerplant

A performance and operational economics analysis is presented for an integrated-gasifier, combined-cycle (IGCC) system to meet the steam and baseload electrical requirements. The effect of time variations in steam and electrial requirements is included. The amount and timing of electricity purchases from sales to the electric utility are determined. The resulting expenses for purchased electricity and revenues from electricity sales are estimated by using an assumed utility rate structure model. Cogeneration results for a range of potential IGCC cogeneration system sizes are compared with the fuel consumption and costs of natural gas and electricity to meet requirements without cogeneration. The results indicate that an IGCC cogeneration system could save about 10 percent of the total fuel energy presently required to supply steam and electrical requirements without cogeneration. Also for the assumed future fuel and electricity prices, an annual operating cost savings of 21 percent to 26 percent could be achieved with such a cogeneration system. An analysis of the effects of electricity price, fuel price, and system availability indicates that the IGCC cogeneration system has a good potential for economical operation over a wide range in these assumptions

Polyimide polymers provide higher char yield for graphitic structures

Technique for manufacture of graphite composites uses high-char-forming processable polyimide resin systems to produce the graphitic matrix. Only three cyclic steps are required to yield a 99.7 percent graphite product

Polyimide polymers provide improved ablative materials

Principle heat absorption of silica-reinforced plastic ablative materials occurs from the in-depth reaction of silica with carbon to form silicon monoxide and carbon monoxide. The higher the degree of completion of this reaction, the higher the capacity of the ablative material to absorb heat

Cluster Winds Blow along Supercluster Axes

Within Abell galaxy clusters containing wide-angle tailed radio sources, there is evidence of a ``prevailing wind'' which directs the WAT jets. We study the alignment of WAT jets and nearby clusters to test the idea that this wind may be a fossil of drainage along large-scale supercluster axes. We also test this idea with a study of the alignment of WAT jets and supercluster axes. Statistical test neighbours indicate no alignment of WAT jets towards nearest clusters, but do indicate approximately 98% confidence in alignment with the long axis of the supercluster in which the cluster lies. We find a preferred scale for such superclusters of order 25 Mpc $h^{-1}$.Comment: Latex, 5 pages, with 5 postscript figures. To be published in MNRAS. Slight revisions to coincide with journal text. Linked to color image at http://kusmos.phsx.ukans.edu/~melott/images/A2634SUW.jp